The present invention is drawn to a novel loudspeaker system and a loudspeaker housing system for capturing and concentrating sound waves that are emitted toward the back side of a plurality of loudspeakers.
In the past, attempts have been made to improve the efficiency of a loudspeaker which is capable of accurately reproducing high-fidelity sound. Specifically, attempts of improvement have been made in two areas of the loudspeaker system: 1) the loudspeaker cone and diaphragm utilizing modern materials; and 2) the housing that encases the loudspeaker, to reduce unwanted vibration and resonation within the housing. A loudspeaker system utilizing or manipulating sound waves directed toward the rear of the speaker has been proposed, for example, in U.S. Pat. No. 4,439,644 to Bruney, III, U.S. Pat. No. 4,524,846 to Whitby, U.S. Pat. No. 4,655,315 to Saville, U.S. Pat. No. 4,807,293 to Weckler, and U.S. Pat. No. 4,930,596 to Saiki et al.
In U.S. Pat. No. 4,439,644 to Bruney, III (Bruney), a loudspeaker system utilizes a plurality of vinyl sheets having different thicknesses to seal the rear of a speaker housing, to relieve pressure behind the loudspeaker driver, and to attenuate sound waves emitted toward the rear of the speaker. While this type of system minimizes the housing vibration and generation of the spring-like compression effect or the resonant booming effect often associated with an acoustic suspension enclosure, the speaker is not as efficient as a ported speaker system in general. Unlike the prior inventions, the present invention captures and concentrates sound waves which are emitted toward the rear of at least two loudspeaker and directs the sound waves to a singular sound concentrating horn and the like.
In U.S. Pat. No. 4,524,846 to Whitby and U.S. Pat. No. 4,807,293 to Weckler, a loudspeaker system directs sound waves radiated rearwardly into the chamber(s) in the housing through a convoluted path. This type is known to provide a fairly reputable performance. However, due to sound waves colliding against baffles stationed in the housing, resonance in the baffle and the housing cannot be avoided when driving at high volume levels, coloring or distorting its true sound.
Additionally, in order to produce a high level output the loudspeaker diaphragm must be large and the thrust distance, i.e., the forward traveling distance, must be relatively long. This structural arrangement for producing a high level output requires a special design and expensive material. Furthermore, because the diaphragm must be large and strong to sustain the high level output, the end result is that the diaphragm will have to possess a large inertia (mass), which reduces diaphragm sensitivity and undesirably increases the response time, thus reducing the high fidelity capability.
In U.S. Pat. No. 4,655,315 to Saville and U.S. Pat. No. 4,930,596 to Saiki et al., a loudspeaker is housed in a specially configured sound collecting tube to modify the frequency response. The efficiency of the speaker, however, in such an arrangement is reduced because the sound travels through restricted openings, which may react much like the baffles in the housing. Furthermore, because of the frequency response modification, colored or distorted sound is likely to occur, whereas in the present invention, a freely aspirated sound collecting tubes do not color the sound and thus the sound generated from the loudspeaker is heard directly without being colored or distorted.
In contrast with the prior speaker system, in the present invention, a high level output is produced by collecting and concentrating sound waves generated from a plurality of smaller rated loudspeakers and output to a single horn. The production cost can be significantly reduced vis-a-vis a single high-level output loudspeaker system, while fully rendering the maximum high-fidelity capability of a smaller rated loudspeaker system because of their smaller inertia and thrust distance. Moreover, there are no baffle or medium which can cause resonation or unwanted sound reflections within the speaker housing. Sound waves passing through the tubes are freely "breathable". In other words, pressure build-up behind the speaker and sound reflections within the confines of the speaker housing, which cause undesirable sound distortion, are avoided or at least minimized by routing and concentrating sound waves through the sound collecting tubes which house the loudspeakers.